George Watts sculpted a head of Medusa while visiting Florence in the 1840s. It is now in Compton's Watts Gallery (there doesn't seem to be any way of linking directly to the page, so you'll have to search for Medusa). (public domain image from museumsyndicate.com)

Arnold Bocklin painted this picture of Medusa in 1878 or thereabouts. It is now in a private collection.

Maximilian Pirner painted the top painting of Medusa in 1891, while Carlos Schwabe painted his Medusa in 1895 I have not been able to find either's present location, so I assume they are both in private collections.

Jacek Malczewski painted this Medusa in 1900. It is now in the Lviv Art Gallery, which does not seem to have a website.

Vincenzo Gemito produced a relief head of Medusa in 1911, which is now in Los Angeles's Getty Center.

To finish off with here is a rather nice cartoon version of the story of Perseus and Medusa produced by ABC and the University of Melbourne. (all images are in the public domain and come from wikicommons unless otherwise credited)